Development of a light-emitting device using a light-emitting element in which a layer including a light-emitting layer is included between a pair of electrodes and which emits light with current applied between the electrodes has been expanded. Such a light-emitting device is more advantageous to reduction in thickness and weight, in comparison with other display devices referred to as thin display devices, has a high level of visibility because of a self-luminous display device, and has fast response speed. Therefore, the light-emitting device has been actively developed as a next-generation display device, and part of the light-emitting device has been put to practical use.
As the above-described light-emitting device, a light-emitting display device is given, in which a light-emitting element in which a layer containing an organic matter, an inorganic matter, or a mixture of an organic matter and an inorganic matter performing light emission referred to as electroluminescence (hereinafter, referred to as “EL”) is interposed between electrodes and a thin film transistor (TFT) are connected to each other.
Since an electroluminescent element (an EL element) can emit light with high luminance, evocative multicolor images can be displayed. For example, luminance of light emission obtained from a light-emitting element is as high as 100 to 10000 cd/m2. Since a light-emitting display device has fast response speed and is self-luminous, the light-display device has advantages in that reduction in thickness and weight is possible. A light-emitting element utilizing electroluminescence, which can be applied to the present invention, is distinguished by whether a light-emitting material is an organic compound or an inorganic compound. In general, the former is referred to as an organic EL element and the latter is referred to as an inorganic EL element.
As a material for separating pixels of an EL element (hereinafter, referred to as a partition wall), a resin material is used (see Patent Document 1: Japanese Published Patent Application No. 2000-294378). Such a resin material is patterned by dry etching or wet etching, or patterned in such a manner that photosensitivity is imparted to a resin itself and exposure and development processes are performed, in some cases.